Firefox scrolling the wrong window

[tumbletree]

Qubes OS version
4

Affected component(s) or functionality
firefox

Brief summary
two firefox windows overlapping. Scrolling on top one did not move the page, but moved a page on the window behind. Clicked several times on page, no change. Clicking around between qubes, and it broke the 'spell', ie working properly now.

To Reproduce
Open Several firefox windows open, each with many tabs (so, ~4 w. x 10 tabs)
open another window (on top), load a page. Move mouse for scroll.

Expected behavior
active page should move with mouse.

Actual behavior
a different page moved with mouse.

Screenshots
If applicable, add screenshots to help explain your problem.

Additional context
I query if there are new issues with firefox on Fedora-31 (I have noticed freezing), but don't know if that's firefox, fedora, my old machine (x230) or something else.

Solutions you've tried
If applicable, any solutions or workarounds you've already tried.

Relevant documentation you've consulted
A list of links to the Qubes documentation (or other relevant software documentation) pages you have already consulted.

Related, non-duplicate issues
A list of links to other bug reports, feature requests, or tasks in the qubes-issues tracker (or "none" if you didn't find any). Do not describe any other unreported bugs, features, or tasks here.

[iamahuman]

The focus issue is a duplicate of #1455 and #3267.

Not sure about freezing though.

[andrewdavidwong]

This appears to be a duplicate of an existing issue. If so, please comment on the appropriate existing issue instead. If you believe this is not really a duplicate, please leave a comment briefly explaining why. We'll be happy to take another look and, if appropriate, reopen this issue. Thank you.